The present invention relates to power control devices and methods, and more particularly, to system architectures and algorithms utilized in GPS receivers.
The Global Positioning System (GPS) is a satellite-based navigation system that requires low power in order to preserve battery life in handheld applications. There are currently three GPS systems: the NAVSTAR Global Positioning System controlled by the United States Defense Department; the GLONASS maintained by the Russian Republic; and the GALILEO system proposed in Europe.
To decode satellite signals, a GPS receiver must first acquire the signals transmitted by a minimum number of satellites. The GPS receiver calculates its position by measuring the distance between itself and the minimum number of satellites that are in general more than three. The signals carry information of the position of the satellites. By determining the positions of the satellites and the distances to the satellites, the GPS receiver is able to determine its position using trilateration. The difficulty in preserving power is that hardware components require a continual power supply in order to track and process signals received from the satellites to generate navigation updates at a required rate.
For handheld GPS devices, the size and the associated weight of the battery impose a limit to the compactness of the GPS devices. Hence, a need exists for an improved GPS receiver that offers lower power consumption than conventional techniques.